The related art discusses various devices used, and suggested in the past for protecting the teeth, tongue, and lips from biting injury during the administration of electroconvulsive therapy. One device, called an "Oberto" cushion, is shown in U.S. Pat. No. 2,521,084. It uses an oral protector made of soft rubber. It is sterilizable and re-usable, which presents various problems, discussed below. The Oberto mouthpiece has a rear biting portion that fits between the teeth, an anterior rim that fits between the teeth and the lips, and a more anterior hollow tube that transmits air or oxygen into the oral cavity and thence to the lungs.
Another mouthpiece, of the type shown in U.S. Pat. No. 5,235,991, is called "PROMAX." That patent is to Dr. Susan Minneman. The "PROMAX" device is a mouthpiece constructed from cardboard and foam. The "PROMAX" is a single-use disposable mouthpiece. It positions cushioning foam only between the molars so if a molar is loose or missing, the uncushioned anterior teeth must bear the load of the bite. In addition, there is no air channel as its thin cardboard anterior portion does not provide any separation of the lips. A third device is called the "BITE-BLOC" and relates to U.S. Pat. No. 4,112,939 of Paul Blachly. That mouthpiece is made from a plastic-like material much harder than rubber. In some cases the Blachly "BITE-BLOC" does not cover even the patient's second molars. That device is made of a hard material which can increase the risk of tooth fracture. A fourth device, which it is believed is not yet marketed (Dr. C. Kellner and Medical U. of South Carolina) uses styrofoam to make a single-use (disposable) mouthprop. The Kellner mouthprop does not have an air channel and may obstruct the flow of air. When used with some commonly used oxygen masks, its anterior portion may extend too far forward and prevent an air-tight seal with the mask.
The prior devices have the following drawbacks:
1. During ECT the jaw muscles contract powerfully, clamping the teeth together with great force. Unless sufficient compressible material is interposed between the teeth, especially between the upper and lower molars during this clamping movement, excess pressure is placed on the weaker incisors, leading to possible tooth fracture. Even if sufficiently compressible material is initially correctly interposed between the molars, unless the mouthpiece oral protector is dimensionally stable, the clamping action of the jaw can laterally displace the protector in either the lingual (tongue's) or buccal (cheek's) direction. That type of slippage can reduce or eliminate the protective effect on the incisors. PA0 2. Unless the mouthpiece oral protector is made from a sufficiently dense and malleable material, the powerful biting action during ECT can dislodge or break off small pieces of the protector. Those pieces may be aspirated, leading to pneumonia and other pulmonary complications. PA0 3. During ECT the brain, heart, and other vital organs require an increased supply of oxygen. Unless the oral protector design permits full and easy flow of oxygen into the oral cavity, and then to the lungs, adverse tissue effects of reduced oxygen availability can occur, including cardiac arrhythmias and brain dysfunction. Moreover, because an oxygen mask is used to deliver oxygen during ECT, the oral protector must not extend so far anteriorly as to block correct positioning of the oxygen mask. PA0 4. Some of the prior mouthpieces are not single-use disposable devices but are intended to be sterilized and re-used. Reusable medical products have transmitted a variety of infectious pathogens between patients. Incomplete decontamination and disinfection are the main causes. Such decontamination is especially a problem with non-metal devices such as mouthpieces. The care of such cross-infections is usually not reimbursed by medical insurance plans. Generally, reusable mouthpieces are disfavored since it is costly to wash, transport, sterilize, and wrap them after each use. In addition, it is necessary to create and maintain records on each re-use, which is a time-consuming burden.
Thus, the key elements of a medically suitable mouthpiece oral protector are as follows:
a. Coverage of all teeth PA1 b. Compressibility PA1 c. Air channel PA1 d. Structural stability PA1 e. Compositional integrity PA1 f. Single use PA1 g. Dimensions compatible with oxygen mask
In view of these key elements, it is seen that the presently commercially available ECT mouthpieces are deficient in one or more respects.
The "OBERTO" reusable model has a tubular air channel which projects far enough anteriorly to occasionally block correct application of the oxygen face mask. This causes the air channel to bend and collapse, defeating its purpose. It is subject to incomplete disinfection/contamination and therefore the possibility of transmitting cross-infections.
The "PROMAX" single-use model lacks sufficient compressible material to protect all teeth. It can be hazardous in the presence of loose or missing teeth. It lacks an air channel, and the presence of only a very thin cardboard surface between the lips can allow the lips to compress anteriorly, blocking the flow of oxygen.
The "BLACHLY BITE-BLOC" reusable model has biting surfaces which extend insufficiently rearward to protect the rearmost (3d) molars in all cases. It is composed of a too-rigid, non-compressible material that can cause tooth damage during the powerful initial biting action during ECT. It also may not be completely disinfected after use, resulting in the possibility of cross-infections.
The "KELLNER MOUTHPROP" is constructed of styrofoam and thus subject to partial disintegration during the shearing force created by the biting action of ECT, raising the risk of aspiration pneumonia. It lacks rear structural stability, raising the possibility of lingual or buccal slippage during biting and loss of the protective function. It lacks a specific air channel. In addition, it extends far enough anteriorly to compromise oxygen mask fit in some patients.